The invention relates to an apparatus for treating fabrics, of the type comprising a first chamber for forming a reserve of infeed fabric, a second chamber for forming a reserve of outfeed fabric, first means for slowly infeeding the fabric into the first chamber, second means for slowly removing the fabric from the second chamber, a duct allowing for the passage therethrough of the fabric between the first chamber and the second chamber, fabric transport means capable of forward and backward operation including nozzles and which is adapted to generate a forward and backward movement of the fabric between the first chamber and the second chamber, and control means, operation of which causes inversion of the forward and backward movement.
Such apparatus are already known. For example, EP-0 653 508 discloses an apparatus for the wet treatment of fabrics having two chambers, slow fabric infeed and delivery means and transport means which move the fabric accumulated in the chambers forward and backward from one of the chambers to the other, thereby allowing the fabric to be more rapidly and effectively treated, and without deterioration thereof due to friction. Such treatments may form a very wide range and there may even be diverse groups of modules each formed by a pair of chambers, such that various treatments may be carried out in series. Similar apparatus are also known for the dry treatment of fabrics.
It is frequently of interest that the fabric be subjected to blows during the treatment, so that it may acquire enhanced softness and handle qualities. Apparatus of the type first mentioned above are known which include a striking device. Thus, for example, EP-0 787 963 discloses an apparatus for the dry treatment of fabrics in which there is to be observed, apart from the two chambers, the fabric infeed and delivery means and the fabric transport means, a striking device comprising a rotor with which the fabric collides during the forward and backward movement thereof.
Nevertheless, these apparatus have drawbacks when it is necessary to work at high speeds, i.e., with very high transport fluid flows and/or fabrics of low specific weight. In these cases, the striking device is less effective, and may even in certain cases cause the fabric to wind around the striking device. It is likewise desirable to intensify the striking effect to increase the performance of the apparatus and allow the treatment times to be shortened.
It is an object of the invention to overcome these drawbacks. This objective is achieved by a fabric treatment apparatus of the type first mentioned above, characterized in that it is provided with at least one collision member adapted to be impacted upon by the fabric, the collision members defining collision surfaces, in that the collision members are adapted to move between a collision position and a free passage position, and in that the movement between the collision position and the free passage position takes place synchronized with the forward and backward movement of the fabric.
In fact, the collision members allow the fabric to undergo a plurality of collisions in each of the directions of forward and backward movement. Furthermore, since the collision members may move between the collision position and the free passage position, the apparatus may be designed in such a way that said collision members are in the collision position when the fabric is moving in one of the directions of the forward and backward movement, while the collision members move to the free passage position when the fabric changes direction, whereby they do not hinder or interfere in the passage of the fabric. This allows the geometry and the position of the collision members to be designed with greater liberty, such that the effect of the blows is optimized.
The apparatus is preferably provided with at least two collision member groups, in such a way that in each direction of the forward and backward movement, at least one of the collision member groups is in the collision position. In this way, the fabric is subjected to the effect of blows in each direction of forward and backward movement, whereby the speed of treatment is doubled relative to the case wherein there are only provided collision members which move into the collision position in one direction of the forward and backward movement.
It is particularly advantageous that the collision members be permeable, or at least partly permeable, to the transport fluid, since, otherwise, the transport fluid is excessively diverted from its original path, causing additional turbulence which makes the transport capacity of the transport fluid less effective and entrains the fabric with it, whereby the effectiveness of the collision of the fabric on the collision members is lowered.
The collision members are preferably formed by substantially rectangular flaps, having at one side a shaft about which they may pivot, so as to pass from the collision position to the free passage position and vice versa. The flap thus forms a wall which is interposed in the path that the fabric would follow in the absence of the collision members, whereby the fabric will collide against the surface of the wall facing the direction of movement of the fabric and which forms the collision surface. There are various ways in which these walls may be formed. They may, for example, be formed by a number of preferably co-planar rods and/or tubes having one end attached to the shaft and the opposite end free. The free ends may optionally be joined together with another rod. Said wall may also be formed by a, for example, metal sheet which may optionally be provided with orifices, allowing for an enhancement of the passage of the transport fluid. The collision surface is generally flat. Nevertheless, it is preferable that in certain cases, said collision surface should not be flat, but should be concave or convex in the direction of incidence of the fabric. An apparatus for the treatment of fabrics according to the invention may have all the collision members identical, or may mount a plurality of mutually different collision members. Furthermore, it is also advantageous for the collision position of the collision members to be adjustable, and it is particularly advantageous that such adjustment may be carried out individually. This adjustment may be desirable both at the start of a treatment, depending on the treatment to be performed and the fabric to be treated, and during the treatment itself.
These collision members are preferably arranged along a duct connecting both chambers. It has been found that it is advantageous to have two additional, also adjustable, collision members, one at each end of the duct connecting both chambers. These additional collision members, apart from the collision function, also have the function of enhancing the piling of the fabric in the corresponding chamber. It is not necessary for these additional collision members to be subjected to movement between the collision position and the free passage position undergone by the remaining collision members, since they are practically outside the path of the fabric, when the latter travels in the opposite direction to the collision direction against the additional collision member, whereby the fabric does not touch the additional collision member and, therefore, it is not necessary for the additional collision member to move to a free passage position, as the remaining collision members do.
The transport means are usually housed at an intermediate point, usually in the mid-point, of the duct connecting both chambers. In certain cases, for example when the duct has an inverted U shape, the transport means are divided into two transport units, each responsible for one direction of movement and between both transport groups, there is a portion of the duct curved in 180 degrees. The fabric, in its forward or backward movement from one chamber to the other, defines a direction of feed or direction of movement, which is also forward or backward. The collision means is preferably arranged on both sides of the transport means, and preferably only those collision members which are downstream of the transport means in the direction of feed of the fabric are in the collision position.
These apparatus are adapted for both dry and wet treatment of fabrics. Likewise, although they are preferably adapted for the treatment of open width fabrics, it is also possible to use apparatus according to the invention for the treatment of fabrics in rope form.
The second means is usually situated in the upper part of the apparatus, approximately above the second chamber. The second means thus removes the fabric from the top of the apparatus, thereby causing the formation of a web of fabric from the bottom of the chamber, where the fabric is alternately accumulated, due to the forward and backward movement, to the top of the apparatus, where it exits the apparatus through the second removal means. In certain cases, the weight of the fabric web may affect the fabric, stretching it for example in the longitudinal direction of the web and contracting it in the transverse direction perpendicular to the web. To avoid these drawbacks, it is preferable to provide the apparatus with removal means having sloping conveyor belts which run from a low point, situated close to the bottom of the second chamber, to a high point and entrain the web of fabric which is resting on the conveyor belt. In this way, the fabric is moved to the top, without being subjected to tensile stress.
The collision members may be driven in different ways. They may, for example, be driven by hydraulic rams. All the collision members may preferably be operated by a single hydraulic ram and a number of levers which transmit the movement to all the collision members. Other drive systems are also possible, such as for example gear trains which may be directly meshed together or which may be associated together with transmission chains. A preferred solution contemplates the possibility of the collision members having individualized drive mechanisms.